JP3786341B2 - Combined steel caisson structure of composite caisson - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a structure in which a steel plate constituting an outer wall and concrete are combined in a composite type (hybrid) caisson applicable to a breakwater, a seawall, and the like.
[0002]
[Prior art]
FIG. 7 is a schematic view of a conventionally produced synthetic caisson in which concrete 4 is pasted on the outer surface of a steel plate box via studs 2. The outer wall is a steel plate in which studs 2 are welded at intervals of about 15 cm. 1 is a structure in which the reinforcing bars 3 assembled in a lattice shape are installed on the steel plate 1 so as to be kept at a certain distance from the steel plate 1 and the concrete 4 is placed. In addition, 6 in FIG. 7 shows a partition.
[0003]
[Problems to be solved by the invention]
However, there are the following problems in the joint structure of the outer wall steel and concrete in the conventional synthetic caisson as described above.
(1) It is necessary to arrange the studs fairly densely.
The design of the composite plate is studied so that local buckling does not occur between the stud intervals with respect to the bending moment in the steel plate on the compression side. In addition, regarding the shearing force, the shear transmission resistance of the stud is examined. According to this result, when the studs 2 are arranged in a staggered arrangement as shown in FIG. 8A or a lattice arrangement as shown in FIG. Both a need to be arranged fairly densely of about 15 cm.
[0004]
Conventionally, there has been a variation in the welding of studs, and there has been a problem in quality.
Furthermore, there is a problem that the upper weld toe portion of the stud is poorly melted and becomes a starting point of fatigue failure.
As described above, recently, there are situations in which studs are not desired to be adopted.
[0005]
(2) Reinforcement ribs for concrete placement are required on the outer wall.
The design strength of the outer wall is sufficiently satisfactory as a composite structure of the steel plate 1 and the reinforced concrete 3 and 4. However, this is a story when the concrete 4 hardens and becomes integrated with the steel plate 1. Before the concrete rod 4 is placed, the reinforcing bar 3 and the steel plate 1 are not integrated but are placed separately. In order to resist the pressure of the flowing concrete 4, it is necessary to reinforce the steel plate 1 with reinforcing ribs.
[0006]
At present, as shown in FIG. 7, the angle member 5 is reinforced by attaching it to the inside of the caisson at a pitch of about 500 mm. This reinforcement is effective as a reinforcing material for the composite plate after the concrete 4 is hardened. However, with respect to the axial force due to water pressure or the like, as shown in FIG. It is necessary to examine the strength to test local buckling by applying an axial force to the attached test material.
[0007]
(3) A large number of spacing members (spacers) are required to maintain the position of the stripe.
At present, the grid-like reinforcing bars 3 are installed apart from the steel plate 1 and the stud 2, but in that case, a large number of spacers are arranged to maintain the distance from the steel plate 1 and to support the vertical weight. It is necessary to install a bracket.
[0008]
An object of the present invention is to provide a steel / concrete combined structure of a composite type caisson that can solve the above-described problems associated with the structure of a steel plate and concrete of an outer wall in a conventional composite type caisson.
[0009]
[Means for Solving the Problems]
In order to achieve the above-described object, the composite caisson steel / concrete bonded structure according to the present invention has a through-hole having a diameter larger than that of the reinforcing bar at a predetermined interval on the outer peripheral side surface of the steel plate box. A perforated reinforcing rib is attached, a reinforcing bar is passed through each through hole of this perforated reinforcing rib, and a grid-like reinforcing bar is placed on the perforated reinforcing rib, and both reinforcing bars are connected by a spiral band. By doing so, concrete is placed in a state where the position of the reinforcing bar is maintained. And by doing in this way, compared with the case where a stud is provided, deviation rigidity becomes very high, and destruction resistance also becomes high. Furthermore, the reinforcing effect of concrete is also increased.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
The steel-concrete bonded structure of the composite caisson according to the present invention is provided with a perforated reinforcing rib provided with a through hole having a diameter larger than that of a reinforcing bar at a predetermined interval on the outer peripheral side surface of a steel plate box. Concrete is placed in a state where the position of the reinforcing bar is maintained by passing the reinforcing bar through each through hole of the opening reinforcing rib.
[0011]
The steel / concrete bonded structure of the composite caisson according to the present invention is characterized in that the function of the stopper and the reinforcing rib is combined with the perforated reinforcing rib.
The perforated reinforcing rib is shown by Leonhard and is not new. However, when its function is shown, as shown in FIG. 6 (a), the concrete 13 wraps around the through-hole 12a provided in the reinforcing bar 11, so that the hole It becomes possible to resist the shearing force between the concrete 13 and the steel plate 14 in the length direction of the opening reinforcing rib 12 (left and right direction in FIG. 6A). Further, the reinforcing bar 11 passed through the through hole 12a exhibits a dowel effect and also shares the shearing force.
[0012]
In addition, as shown in FIG. 6B, in the direction perpendicular to the length of the perforated reinforcing rib 12 (vertical direction in FIG. 6B), the perforated reinforcing rib 12 is subjected to shearing force in the same manner as the stud. resist. Further, the reinforcing bar 11 passed through the through hole 12 a resists the crack 13 a of the concrete 13.
[0013]
In this way, when perforated reinforcing ribs are used to reinforce steel plate boxes, the displacement rigidity is very high compared to the case where studs are provided, and the fracture strength is also high. Therefore, better results can be obtained than when studs are provided.
[0014]
In addition, in the steel / concrete bonded structure of the composite caisson according to the present invention, in addition to the reinforcing bar through which the through hole of the perforated reinforcing rib passes, a grid-like reinforcing bar is further arranged on the perforated reinforcing rib, Since they are connected by the spiral band, a truss structure is formed between the reinforcing bar through which the through hole passes and the vertical reinforcing bar of the latticed reinforcing bar, and the reinforcing effect of the concrete is increased.
[0015]
In this case, since the reinforcing bar contacts the perforated reinforcing rib and does not shift downward, it is possible to prevent the lattice reinforcing bar and the reinforcing bar passing through the through hole from being shifted downward. In general, the band has a small hoop shape, but by making the whole into a spiral shape, it becomes easy to handle without making a small part.
[0016]
In the steel / concrete bonded structure of the composite caisson according to the present invention described above, the through hole of the reinforcing bar provided in the perforated reinforcing rib has a diameter slightly larger than that of the reinforcing bar, and has a diameter larger than that of the through hole. When the through hole is provided, the following effects can be obtained.
[0017]
For example, considering the case where the reinforcing bar is inserted into the through hole of the perforated reinforcing rib and the case where the reinforcing bar is not inserted into the through hole, the case where the reinforcing bar is not inserted into the through hole is as follows.
1) A shear area equivalent to the area of the through hole is obtained by the concrete that has entered the through hole.
2) The shear area is not destroyed by the reinforcing bars.
[0018]
On the other hand, when the reinforcing bar is inserted into the through-hole, it is as follows compared to the case where the reinforcing bar is not inserted.
(1) Since there is no reinforcing bar in the through hole, it is possible to prevent the concrete from separating on both sides of the perforated reinforcing rib.
(2) Even if the concrete in the through hole is sheared and destroyed due to the dowel effect of the reinforcing bars, the reinforcing bars share the shearing force.
[0019]
In this way, when the reinforcing bar is passed through the through hole, it is inevitable that the concrete shear area of the through hole is disturbed, although there are two merits such as (1) and (2).
[0020]
Therefore, there are two types of through-holes provided in the perforated reinforcing ribs, one that passes through the reinforcing bars and one that does not pass through the reinforcing bars. The through-holes that pass the reinforcing bars are only slightly larger than the diameter of the reinforcing bars, while expecting the shearing force of the concrete The diameter of the through hole is 60 to 70 mm, which is larger than the diameter of the through hole through which the reinforcing bar passes, so that the holding position of the reinforcing bar is fixed and the dowel effect can be obtained with certainty. In the concrete part of the hole, the shear strength is clearly obtained.
[0021]
【Example】
Hereinafter, the steel / concrete combined structure of the composite caisson according to the present invention will be described based on the embodiments shown in FIGS.
FIG. 1 is an overall structural view showing a schematic structure of a first embodiment of a steel / concrete bonded structure of a composite caisson according to the present invention, FIG. 2 is an enlarged view of a main part of FIG. 1, and FIG. 3 is a side view of FIG. FIG. 4 is a view similar to FIG. 2 showing a second embodiment of the steel / concrete bonded structure of the composite caisson according to the present invention, and FIG. 5 is a steel / concrete bonded structure of the composite caisson according to the present invention. It is a figure similar to FIG. 3 which shows 2nd Example of this.
[0022]
1 to 3, reference numeral 21 denotes an outer wall of a composite type caisson that employs a steel plate-concrete bonding structure according to the present invention. In addition to the steel plate 22, the reinforcing bar 23, the grid-like reinforcing bar 24, and the concrete 25, A perforated reinforcing rib 26 that also serves as a stud) and a reinforcing rib, and a band 27.
[0023]
Of these, as shown in FIG. 2, the perforated reinforcing rib 26 is formed by providing through holes 26a having a diameter of 70 to 80 mm at a pitch of about 200 mm on a steel strip having a height of about 120 mm, in which a reinforcing bar 22 is provided. Let go through. The plate thickness of the perforated reinforcing rib 26 varies depending on the pressure because the pressure varies in the height direction.
[0024]
Moreover, since the outer wall 21 is deformed between the partition walls 28, it is desirable that the perforated reinforcing ribs 26 are disposed horizontally so as to hang over the partition walls 28. Therefore, the reinforcing bar 23 through which the through hole 26a passes is in the vertical direction.
[0025]
Next, the band 27 is used to connect the reinforcing bar 23 through which the through hole 26a of the perforated reinforcing rib 26 passes and the lattice reinforcing bar 24 arranged on the perforated reinforcing rib 26, and is processed into a spiral shape. Is. In addition, the band 27 and the grid | lattice-like reinforcement 24 are bound by the annealing iron wire 29, and are tied up.
[0026]
As shown in FIG. 3, the spiral band 27 is first extended upward to surround the reinforcing bar 23 that has passed through the through hole 26 a of the perforated reinforcing rib 26. The steel sheet 22 is bent so as to cover the horizontal reinforcing bar 24 a and the vertical reinforcing bar 24 b and bent toward the steel plate 22 side. Then, it is bent so as to contact the perforated reinforcing rib 26 while descending to the reinforcing bar 23.
[0027]
For example, the helical rebar 27 is manufactured in a state where the lattice rebar 24 and the rebar 27 are secured in a factory, and the rebar unit is carried to the site to form a steel plate 22 constituting the outer wall 21. In this case, the rebar 23 is hooked at the same time as it passes through the through hole 26 a of the perforated reinforcing rib 26.
In this way, the reinforcing bars 23 and the grid-like reinforcing bars 24 are drawn up using the band bars 27, and then the concrete rod 25 is driven and processed as a composite plate.
[0028]
In the first embodiment shown in FIG. 1 to FIG. 3 described above, by using the perforated reinforcing rib 26 as the reinforcement of the steel plate box, the displacement rigidity is very high as compared with the case where the stud is provided. In addition to increasing the fracture resistance, the reinforcing bar 23 and the grid-like reinforcing bar 24 that pass through the through hole 26a are connected by the spiral band 27, so that the upper and lower of the reinforcing bar 23 and the grid-like reinforcing bar 24 The reinforcing effect of the concrete 25 is increased by the truss structure with the directional reinforcing bars 24b. Further, since the band 27 does not shift downward in contact with the perforated reinforcing rib 26, it is possible to prevent the reinforcing bars 23 and the grid-like reinforcing bars 24 that are secured together from shifting downward.
[0029]
The present invention is not limited to the embodiment shown in FIGS. 1 to 3, and as shown in FIG. 4, the through hole provided in the perforated reinforcing rib 26 is not connected to the through hole 26 a through which the reinforcing bar 23 passes. Two types of through-holes 26a through which the reinforcing bars 23 pass are made slightly larger than the diameter of the reinforcing bars 23, while the through-holes 26b that expect the shearing force of the concrete 25 have a diameter of 60 to 70 mm and the reinforcing bars 23. The diameter may be larger than the through-hole 26a to be passed.
[0030]
By doing so, the holding position of the reinforcing bar 23 is fixed, and the dowel effect is surely obtained, and the shear strength is clearly obtained in the concrete 25 portion of the large-diameter through hole 26b. Become.
[0031]
In addition , when the thickness of the concrete 25 may be thin, as shown in FIG. 5, the reinforcing bars 23 are not attached to the lattice reinforcing bars 24, that is, the through holes 26 a provided in the perforated reinforcing ribs 26. It may be the one that has just been passed through and concrete 25 is cast. In this case, although not shown, it goes without saying that the reinforcing bar 23 is bound to the perforated reinforcing rib 26 with an annealed iron wire and secured.
[0032]
【The invention's effect】
As described above, according to the steel / concrete bonded structure of the composite caisson according to the present invention, the following effects can be obtained.
1. By applying the perforated reinforcing rib to the composite caisson structure, the work of welding many studs is eliminated, and the process is greatly simplified. In addition, the stud has a variation in welding and has been a problem in terms of quality. However, since the perforated reinforcing rib can perform sufficient welding management, the quality problem is eliminated.
[0033]
2. In the welding of the stud, the penetration of the stud-side upper weld toe portion is poor, and this portion is the starting point of fatigue failure, but such a problem does not occur in the perforated reinforcing rib.
3. Since the perforated reinforcing rib serves as both a conventional stud and a reinforcing rib, the number of members can be reduced. Further, since the perforated reinforcing rib is embedded in the concrete, there is little concern about buckling.
[0034]
4). Since the connecting reinforcing bars and the lattice-like reinforcement obliquely, it is possible to enhance the reinforcing effect of concrete by truss effect. And, since the connection of iron muscles and the lattice-shaped reinforcing bars are carried out by the helical band muscle, it can be reduced of the quantity of the hoop.
5. Since the spiral strips come into contact with the perforated reinforcing ribs at many points, the weights of the reinforcing bars and the lattice reinforcing bars can be supported, and the reinforcing bars can be easily supported in the vertical direction.
[Brief description of the drawings]
FIG. 1 is an overall structural diagram showing a schematic structure of a first embodiment of a steel / concrete bonded structure of a synthetic caisson according to the present invention.
FIG. 2 is an enlarged view of a main part of FIG.
FIG. 3 is a view of FIG. 2 as viewed from the side.
FIG. 4 is a view similar to FIG. 2 showing a second embodiment of the steel / concrete bonded structure of a synthetic caisson according to the present invention.
FIG. 5 is a view similar to FIG. 3 showing a second embodiment of the combined steel / concrete structure of a composite caisson according to the present invention.
6A and 6B are diagrams for explaining the function of the perforated reinforcing ribs, where FIG. 6A is a diagram viewed from a plane direction, and FIG. 6B is a diagram viewed from a side surface direction;
FIG. 7 is a schematic view of a synthetic caisson.
FIGS. 8A and 8B are explanatory diagrams in the case of examining the stud interval with respect to the bending moment in the compression side steel plate when designing the composite plate, where FIG. 8A is a staggered arrangement and FIG. 8B is a lattice arrangement.
FIG. 9 is an explanatory diagram when a local buckling or the like is tested by applying an axial force to a test material having angle members attached to the front and back surfaces of a steel plate.
[Explanation of symbols]
21 Outer Wall 22 Steel Plate 23 Reinforcement 24 Grid-like Reinforcement 25 Concrete 26 Perforated Reinforcement Rib 26a Through Hole 26b Through Hole 27 Band Reinforcement

Claims (2)

At the outer peripheral side of the steel plate box, a perforated reinforcing rib with a predetermined interval and a through hole larger in diameter than the reinforcing bar is attached,
Reinforcing the reinforcing bar through each through-hole of the perforated reinforcing rib, and placing a reinforcing bar in the form of a grid on the perforated reinforcing rib, and connecting the two reinforcing bars with a spiral band reinforcing the position of the reinforcing bar A combined caisson steel / concrete structure, characterized in that the concrete is cast in a state where the material has been applied.   2. The composite caisson according to claim 1, wherein the through hole of the reinforcing bar provided in the perforated reinforcing rib has a diameter slightly larger than that of the reinforcing bar, and further, a through hole having a diameter larger than the through hole is provided. Steel / concrete combined structure.

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